Relay discovery in wireless communication systems

ABSTRACT

A configuration for dynamically updating the neighbor list sent to a UE based on the location of the UE and the location of one or more mobile relays. The apparatus receives first location information for one or more UEs. The apparatus receives second location information for one or more mobile relays. The apparatus determines a distance between the one or more UEs and each of the one or more mobile relays. The apparatus sends assistance information to at least one of the one or more UEs in an area, the assistance information identifying at least one mobile relay of the one or more mobile relays based on the determined distance between the one or more UEs and the at least one mobile relay.

CROSS-REFERENCE TO RELATED APPLICATION(S)

This application claims the benefit of Greek Application Serial No.20190100399, entitled “RELAY DISCOVERY IN WIRELESS COMMUNICATIONSYSTEMS” and filed on Sep. 16, 2019, the contents of which are expresslyincorporated by reference herein in their entirety.

BACKGROUND Technical Field

The present disclosure relates generally to communication systems, andmore particularly, to discovery of relays in wireless communicationsystems.

Introduction

Wireless communication systems are widely deployed to provide varioustelecommunication services such as telephony, video, data, messaging,and broadcasts. Typical wireless communication systems may employmultiple-access technologies capable of supporting communication withmultiple users by sharing available system resources. Examples of suchmultiple-access technologies include code division multiple access(CDMA) systems, time division multiple access (TDMA) systems, frequencydivision multiple access (FDMA) systems, orthogonal frequency divisionmultiple access (OFDMA) systems, single-carrier frequency divisionmultiple access (SC-FDMA) systems, and time division synchronous codedivision multiple access (TD-SCDMA) systems.

These multiple access technologies have been adopted in varioustelecommunication standards to provide a common protocol that enablesdifferent wireless devices to communicate on a municipal, national,regional, and even global level. An example telecommunication standardis 5G New Radio (NR). 5G NR is part of a continuous mobile broadbandevolution promulgated by Third Generation Partnership Project (3GPP) tomeet new requirements associated with latency, reliability, security,scalability (e.g., with Internet of Things (IoT)), and otherrequirements. 5G NR includes services associated with enhanced mobilebroadband (eMBB), massive machine type communications (mMTC), and ultrareliable low latency communications (URLLC). Some aspects of 5G NR maybe based on the 4G Long Term Evolution (LTE) standard. There exists aneed for further improvements in 5G NR technology. These improvementsmay also be applicable to other multi-access technologies and thetelecommunication standards that employ these technologies.

SUMMARY

The following presents a simplified summary of one or more aspects inorder to provide a basic understanding of such aspects. This summary isnot an extensive overview of all contemplated aspects, and is intendedto neither identify key or critical elements of all aspects nordelineate the scope of any or all aspects. Its sole purpose is topresent some concepts of one or more aspects in a simplified form as aprelude to the more detailed description that is presented later.

In wireless communication systems (e.g., 5G NR), base stations may havea limited coverage area. Including relay nodes in the wirelesscommunication system allows the relay node to provide additionalcoverage that may not be provided by the limited coverage area of a basestation. Relay nodes can relay the signal from the base station and canexpand or enhance the serving area of the base station. Relay nodes maybe stationary or they may be mobile. For mobile relays, a relay isplaced in a vehicle and may provide coverage to neighboring UserEquipments (UEs), which can be in the vehicle itself or in the vicinityof the vehicle. The relay obtains signal coverage from a stationary basestation (e.g., gNodeB (gNB)) in the wireless network. These basestations may be knowns as donor gNBs.

Base stations may maintain neighbor lists which contain a list ofneighboring cells. In wireless communication systems, the base stationsare fixed and stationary, such that the list of neighboring cells that aUE is expected to see and potentially handover to is known and fixed.However, in wireless communication systems that include relays, e.g.,mobile relays, the relays that provide service to UEs may be mobile,such that a list of neighboring relays that the UE is expected to see ona particular relay may repeatedly change. A UE in idle mode, camped on amobile relay, may select the best cell based on the UE's scanning, whichmay lead to increased reselections and inefficient use of resources. AUE in connected mode, camped on a mobile relay, may be configured toreceive updated neighbor lists to ensure successful handovers toneighboring relays. Aspects provided herein provide a solution to theproblem of dynamically updating the neighbor list sent to the UE, basedon the location of the UE and/or the location of the relays populating aknown cell or another region in the vicinity of the UE at a given time.

In an aspect of the disclosure, a method, a computer-readable medium,and an apparatus are provided. For example, according to one aspect, amethod of wireless communication for a network entity is disclosed. Thenetwork entity receives first location information for one or more userequipments (UEs), and second location information for one or more mobilerelays. The network entity determines a distance between the one or moreUEs and each of the one or more mobile relays. The network entity sendsassistance information to at least one of the one or more UEs in anarea, the assistance information identifying at least one mobile relayof the one or more mobile relays based on the determined distancebetween the one or more UEs and the at least one mobile relay.

According to another aspect of the disclosure, a method of wirelesscommunication at a user equipment (UE) is disclosed. The UE provideslocation information for the UE to a base station. The UE receives, froma network entity, assistance information identifying at least one mobilerelay within a distance of the UE.

According to another aspect of the disclosure, a method of wirelesscommunication at a mobile relay device is disclosed. The mobile relaydevice determines if the mobile relay device is capable of supporting anadditional user equipment (UE) based on a current load of the mobilerelay device. The mobile relay device transmits an indication indicatingwhether the mobile relay device is capable of accepting the additionalUE.

According to another aspect of the disclosure, a method of wirelesscommunication at a base station is disclosed. The base stationdetermines if the base station is capable of supporting an additionalmobile relay based on a current load of the base station. The basestation transmits an indication indicating whether the base station iscapable of accepting the additional mobile relay.

To the accomplishment of the foregoing and related ends, the one or moreaspects comprise the features hereinafter fully described andparticularly pointed out in the claims. The following description andthe annexed drawings set forth in detail certain illustrative featuresof the one or more aspects. These features are indicative, however, ofbut a few of the various ways in which the principles of various aspectsmay be employed, and this description is intended to include all suchaspects and their equivalents.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagram illustrating an example of a wireless communicationssystem and an access network.

FIGS. 2A, 2B, 2C, and 2D are diagrams illustrating examples of a first5G/NR frame, DL channels within a 5G/NR subframe, a second 5G/NR frame,and UL channels within a 5G/NR subframe, respectively.

FIG. 3 is a diagram illustrating an example of a base station and userequipment (UE) in an access network.

FIG. 4 is a diagram illustrating an example of a base station, a UE, anda mobile relay in an access network in accordance to certain aspects ofthe disclosure.

FIG. 5 is a diagram illustrating an example communication systemincluding a base station, UE, and a mobile relay in an access network inaccordance to certain aspects of the disclosure.

FIG. 6 is a diagram illustrating an example communication systemincluding a base station, UE, and a mobile relay in an access network inaccordance to certain aspects of the disclosure.

FIG. 7A is a call flow diagram of signaling between a UE, relay, andbase station in accordance to certain aspects of the disclosure.

FIG. 7B illustrates a continued call flow diagram from FIG. 7A.

FIG. 8 is a flowchart of a method of wireless communication.

FIG. 9 is a flowchart of a method of wireless communication.

FIG. 10 is a flowchart of a method of wireless communication.

FIG. 11 is a flowchart of a method of wireless communication.

FIG. 12 is a flowchart of a method of wireless communication.

FIG. 13 is a flowchart of a method of wireless communication.

FIG. 14 is a flowchart of a method of wireless communication.

FIG. 15 is a flowchart of a method of wireless communication.

FIG. 16 is a conceptual data flow diagram illustrating the data flowbetween different means/components in an example apparatus.

FIG. 17 is a diagram illustrating an example of a hardwareimplementation for an apparatus employing a processing system.

FIG. 18 is a conceptual data flow diagram illustrating the data flowbetween different means/components in an example apparatus.

FIG. 19 is a diagram illustrating an example of a hardwareimplementation for an apparatus employing a processing system.

FIG. 20 is a conceptual data flow diagram illustrating the data flowbetween different means/components in an example apparatus.

FIG. 21 is a diagram illustrating an example of a hardwareimplementation for an apparatus employing a processing system.

DETAILED DESCRIPTION

The detailed description set forth below in connection with the appendeddrawings is intended as a description of various configurations and isnot intended to represent the only configurations in which the conceptsdescribed herein may be practiced. The detailed description includesspecific details for the purpose of providing a thorough understandingof various concepts. However, it will be apparent to those skilled inthe art that these concepts may be practiced without these specificdetails. In some instances, well known structures and components areshown in block diagram form in order to avoid obscuring such concepts.

Several aspects of telecommunication systems will now be presented withreference to various apparatus and methods. These apparatus and methodswill be described in the following detailed description and illustratedin the accompanying drawings by various blocks, components, circuits,processes, algorithms, etc. (collectively referred to as “elements”).These elements may be implemented using electronic hardware, computersoftware, or any combination thereof. Whether such elements areimplemented as hardware or software depends upon the particularapplication and design constraints imposed on the overall system.

By way of example, an element, or any portion of an element, or anycombination of elements may be implemented as a “processing system” thatincludes one or more processors. Examples of processors includemicroprocessors, microcontrollers, graphics processing units (GPUs),central processing units (CPUs), application processors, digital signalprocessors (DSPs), reduced instruction set computing (RISC) processors,systems on a chip (SoC), baseband processors, field programmable gatearrays (FPGAs), programmable logic devices (PLDs), state machines, gatedlogic, discrete hardware circuits, and other suitable hardwareconfigured to perform the various functionality described throughoutthis disclosure. One or more processors in the processing system mayexecute software. Software shall be construed broadly to meaninstructions, instruction sets, code, code segments, program code,programs, subprograms, software components, applications, softwareapplications, software packages, routines, subroutines, objects,executables, threads of execution, procedures, functions, etc., whetherreferred to as software, firmware, middleware, microcode, hardwaredescription language, or otherwise.

Accordingly, in one or more example embodiments, the functions describedmay be implemented in hardware, software, or any combination thereof. Ifimplemented in software, the functions may be stored on or encoded asone or more instructions or code on a computer-readable medium.Computer-readable media includes computer storage media. Storage mediamay be any available media that can be accessed by a computer. By way ofexample, and not limitation, such computer-readable media can comprise arandom-access memory (RAM), a read-only memory (ROM), an electricallyerasable programmable ROM (EEPROM), optical disk storage, magnetic diskstorage, other magnetic storage devices, combinations of theaforementioned types of computer-readable media, or any other mediumthat can be used to store computer executable code in the form ofinstructions or data structures that can be accessed by a computer.

FIG. 1 is a diagram illustrating an example of a wireless communicationssystem and an access network 100. The wireless communications system(also referred to as a wireless wide area network (WWAN)) includes basestations 102, UEs 104, an Evolved Packet Core (EPC) 160, and anothercore network 190 (e.g., a 5G Core (5GC)). The base stations 102 mayinclude macrocells (high power cellular base station) and/or small cells(low power cellular base station). The macrocells include base stations.The small cells include femtocells, picocells, and microcells.

The base stations 102 configured for 4G LTE (collectively referred to asEvolved Universal Mobile Telecommunications System (UMTS) TerrestrialRadio Access Network (E-UTRAN)) may interface with the EPC 160 throughbackhaul links 132 (e.g., S1 interface). The base stations 102configured for 5G NR (collectively referred to as Next Generation RAN(NG-RAN)) may interface with core network 190 through backhaul links184. In addition to other functions, the base stations 102 may performone or more of the following functions: transfer of user data, radiochannel ciphering and deciphering, integrity protection, headercompression, mobility control functions (e.g., handover, dualconnectivity), inter-cell interference coordination, connection setupand release, load balancing, distribution for non-access stratum (NAS)messages, NAS node selection, synchronization, radio access network(RAN) sharing, multimedia broadcast multicast service (MBMS), subscriberand equipment trace, RAN information management (RIM), paging,positioning, and delivery of warning messages. The base stations 102 maycommunicate directly or indirectly (e.g., through the EPC 160 or corenetwork 190) with each other over backhaul links 134 (e.g., X2interface). The backhaul links 134 may be wired or wireless.

The base stations 102 may wirelessly communicate with the UEs 104. Eachof the base stations 102 may provide communication coverage for arespective geographic coverage area 110. There may be overlappinggeographic coverage areas 110. For example, the small cell 102′ may havea coverage area 110′ that overlaps the coverage area 110 of one or moremacro base stations 102. A network that includes both small cell andmacrocells may be known as a heterogeneous network. A heterogeneousnetwork may also include Home Evolved Node Bs (eNBs) (HeNBs), which mayprovide service to a restricted group known as a closed subscriber group(CSG). The communication links 120 between the base stations 102 and theUEs 104 may include uplink (UL) (also referred to as reverse link)transmissions from a UE 104 to a base station 102 and/or downlink (DL)(also referred to as forward link) transmissions from a base station 102to a UE 104. The communication links 120 may use multiple-input andmultiple-output (MIMO) antenna technology, including spatialmultiplexing, beamforming, and/or transmit diversity. The communicationlinks may be through one or more carriers. The base stations 102/UEs 104may use spectrum up to Y MHz (e.g., 5, 10, 15, 20, 100, 400, etc. MHz)bandwidth per carrier allocated in a carrier aggregation of up to atotal of Yx MHz (x component carriers) used for transmission in eachdirection. The carriers may or may not be adjacent to each other.Allocation of carriers may be asymmetric with respect to DL and UL(e.g., more or fewer carriers may be allocated for DL than for UL). Thecomponent carriers may include a primary component carrier and one ormore secondary component carriers. A primary component carrier may bereferred to as a primary cell (PCell) and a secondary component carriermay be referred to as a secondary cell (SCell).

Certain UEs 104 may communicate with each other using device-to-device(D2D) communication link 158. The D2D communication link 158 may use theDL/UL WWAN spectrum. The D2D communication link 158 may use one or moresidelink channels, such as a physical sidelink broadcast channel(PSBCH), a physical sidelink discovery channel (PSDCH), a physicalsidelink shared channel (PSSCH), and a physical sidelink control channel(PSCCH). D2D communication may be through a variety of wireless D2Dcommunications systems, such as for example, FlashLinQ, WiMedia,Bluetooth, ZigBee, Wi-Fi based on the IEEE 802.11 standard, LTE, or NR.

The wireless communications system may further include a Wi-Fi accesspoint (AP) 150 in communication with Wi-Fi stations (STAs) 152 viacommunication links 154 in a 5 GHz unlicensed frequency spectrum. Whencommunicating in an unlicensed frequency spectrum, the STAs 152/AP 150may perform a clear channel assessment (CCA) prior to communicating inorder to determine whether the channel is available.

The small cell 102′ may operate in a licensed and/or an unlicensedfrequency spectrum. When operating in an unlicensed frequency spectrum,the small cell 102′ may employ NR and use the same 5 GHz unlicensedfrequency spectrum as used by the Wi-Fi AP 150. The small cell 102′,employing NR in an unlicensed frequency spectrum, may boost coverage toand/or increase capacity of the access network.

A base station 102, whether a small cell 102′ or a large cell (e.g.,macro base station), may include an eNB, gNodeB (gNB), or another typeof base station. Some base stations 180, such as a gNB, may operate in atraditional sub 6 GHz spectrum, in millimeter wave (mmW) frequencies,and/or near mmW frequencies in communication with the UE 104. When thegNB operates in mmW or near mmW frequencies, the gNB may be referred toas an mmW base station. Extremely high frequency (EHF) is part of the RFin the electromagnetic spectrum. EHF has a range of 30 GHz to 300 GHzand a wavelength between 1 millimeter and 10 millimeters. Radio waves inthe band may be referred to as a millimeter wave. Near mmW may extenddown to a frequency of 3 GHz with a wavelength of 100 millimeters. Thesuper high frequency (SHF) band extends between 3 GHz and 30 GHz, alsoreferred to as centimeter wave. Communications using the mmW/near mmWradio frequency band (e.g., 3 GHz −300 GHz) has extremely high path lossand a short range. The mmW base station, e.g., the base station 180, mayutilize beamforming 182 with the UE 104 to compensate for the extremelyhigh path loss and short range.

The base station 180 may transmit a beamformed signal to the UE 104 inone or more transmit directions 182′. The UE 104 may receive thebeamformed signal from the base station 180 in one or more receivedirections 182″. The UE 104 may also transmit a beamformed signal to thebase station 180 in one or more transmit directions. The base station180 may receive the beamformed signal from the UE 104 in one or morereceive directions. The base station 180/UE 104 may perform beamtraining to determine the best receive and transmit directions for eachof the base station 180/UE 104. The transmit and receive directions forthe base station 180 may or may not be the same. The transmit andreceive directions for the UE 104 may or may not be the same.

The EPC 160 may include a Mobility Management Entity (MME) 162, otherMMES 164, a Serving Gateway 166, a Multimedia Broadcast MulticastService (MBMS) Gateway 168, a Broadcast Multicast Service Center (BM-SC)170, and a Packet Data Network (PDN) Gateway 172. The MME 162 may be incommunication with a Home Subscriber Server (HSS) 174. The MME 162 isthe control node that processes the signaling between the UEs 104 andthe EPC 160. Generally, the MME 162 provides bearer and connectionmanagement. All user Internet protocol (IP) packets are transferredthrough the Serving Gateway 166, which itself is connected to the PDNGateway 172. The PDN Gateway 172 provides UE IP address allocation aswell as other functions. The PDN Gateway 172 and the BM-SC 170 areconnected to the IP Services 176. The IP Services 176 may include theInternet, an intranet, an IP Multimedia Subsystem (IMS), a PS StreamingService, and/or other IP services. The BM-SC 170 may provide functionsfor MBMS user service provisioning and delivery. The BM-SC 170 may serveas an entry point for content provider MBMS transmission, may be used toauthorize and initiate MBMS Bearer Services within a public land mobilenetwork (PLMN), and may be used to schedule MBMS transmissions. The MBMSGateway 168 may be used to distribute MBMS traffic to the base stations102 belonging to a Multicast Broadcast Single Frequency Network (MBSFN)area broadcasting a particular service, and may be responsible forsession management (start/stop) and for collecting eMBMS relatedcharging information.

The core network 190 may include an Access and Mobility ManagementFunction (AMF) 192, other AMFs 193, a Session Management Function (SMF)194, and a User Plane Function (UPF) 195. The AMF 192 may be incommunication with a Unified Data Management (UDM) 196. The AMF 192 isthe control node that processes the signaling between the UEs 104 andthe core network 190. Generally, the AMF 192 provides QoS flow andsession management. All user Internet protocol (IP) packets aretransferred through the UPF 195. The UPF 195 provides UE IP addressallocation as well as other functions. The UPF 195 is connected to theIP Services 197. The IP Services 197 may include the Internet, anintranet, an IP Multimedia Subsystem (IMS), a PS Streaming Service,and/or other IP services.

The base station may also be referred to as a gNB, Node B, evolved NodeB (eNB), an access point, a base transceiver station, a radio basestation, a radio transceiver, a transceiver function, a basic serviceset (BSS), an extended service set (ESS), a transmit reception point(TRP), or some other suitable terminology. The base station 102 providesan access point to the EPC 160 or core network 190 for a UE 104.Examples of UEs 104 include a cellular phone, a smart phone, a sessioninitiation protocol (SIP) phone, a laptop, a personal digital assistant(PDA), a satellite radio, a global positioning system, a multimediadevice, a video device, a digital audio player (e.g., MP3 player), acamera, a game console, a tablet, a smart device, a wearable device, avehicle, an electric meter, a gas pump, a large or small kitchenappliance, a healthcare device, an implant, a sensor/actuator, adisplay, or any other similar functioning device. Some of the UEs 104may be referred to as IoT devices (e.g., parking meter, gas pump,toaster, vehicles, heart monitor, etc.). The UE 104 may also be referredto as a station, a mobile station, a subscriber station, a mobile unit,a subscriber unit, a wireless unit, a remote unit, a mobile device, awireless device, a wireless communications device, a remote device, amobile subscriber station, an access terminal, a mobile terminal, awireless terminal, a remote terminal, a handset, a user agent, a mobileclient, a client, or some other suitable terminology.

Referring again to FIG. 1, in certain aspects, the base station 102/180may be configured to determine which mobile relays are within thevicinity of a UE and send this information to the UE. For example, anetwork entity in FIG. 1 may include an assistance information component198 configured to provide assistance information to the UE identifyingat least one mobile relay based on the distance between the UE and theat least one mobile relay, such as mobile relay 107. The network entitymay comprise a base station 102 or 180 or may comprise a component of acore network, such as core network 190 or EPC 160. The network entitymay receive location information from UE(s) and mobile relay(s), anddetermine a distance between the UE(s) and the mobile relay(s).

Referring again to FIG. 1, in certain aspects, the UE 104 may beconfigured to discover mobile relays that may be within the vicinity ofthe UE. For example, the UE 104 of FIG. 1 may include a discovercomponent 199 configured to perform discovery for a mobile relay 107based on assistance information received from a network entity. The UE104 may provide location information to a base station, and may receive,from a network entity, assistance information that identifies at leastone mobile relay within a distance of the UE. The UE may establish aconnection 171 with the mobile relay to communication information to thenetwork, e.g., to a base station 102 or 180.

Although the following description may be focused on 5G NR, the conceptsdescribed herein may be applicable to other similar areas, such as LTE,LTE-A, CDMA, GSM, and other wireless technologies.

FIG. 2A is a diagram 200 illustrating an example of a first subframewithin a 5G/NR frame structure. FIG. 2B is a diagram 230 illustrating anexample of DL channels within a 5G/NR subframe. FIG. 2C is a diagram 250illustrating an example of a second subframe within a 5G/NR framestructure. FIG. 2D is a diagram 280 illustrating an example of ULchannels within a 5G/NR subframe. The 5G/NR frame structure may be FDDin which for a particular set of subcarriers (carrier system bandwidth),subframes within the set of subcarriers are dedicated for either DL orUL, or may be TDD in which for a particular set of subcarriers (carriersystem bandwidth), subframes within the set of subcarriers are dedicatedfor both DL and UL. In the examples provided by FIGS. 2A, 2C, the 5G/NRframe structure is assumed to be TDD, with subframe 4 being configuredwith slot format 28 (with mostly DL), where D is DL, U is UL, and X isflexible for use between DL/UL, and subframe 3 being configured withslot format 34 (with mostly UL). While subframes 3, 4 are shown withslot formats 34, 28, respectively, any particular subframe may beconfigured with any of the various available slot formats 0-61. Slotformats 0, 1 are all DL, UL, respectively. Other slot formats 2-61include a mix of DL, UL, and flexible symbols. UEs are configured withthe slot format (dynamically through DL control information (DCI), orsemi-statically/statically through radio resource control (RRC)signaling) through a received slot format indicator (SFI). Note that thedescription infra applies also to a 5G/NR frame structure that is TDD.

Other wireless communication technologies may have a different framestructure and/or different channels. A frame (10 ms) may be divided into10 equally sized subframes (1 ms). Each subframe may include one or moretime slots. Subframes may also include mini-slots, which may include 7,4, or 2 symbols. Each slot may include 7 or 14 symbols, depending on theslot configuration. For slot configuration 0, each slot may include 14symbols, and for slot configuration 1, each slot may include 7 symbols.The symbols on DL may be cyclic prefix (CP) OFDM (CP-OFDM) symbols. Thesymbols on UL may be CP-OFDM symbols (for high throughput scenarios) ordiscrete Fourier transform (DFT) spread OFDM (DFT-s-OFDM) symbols (alsoreferred to as single carrier frequency-division multiple access(SC-FDMA) symbols) (for power limited scenarios; limited to a singlestream transmission). The number of slots within a subframe is based onthe slot configuration and the numerology. For slot configuration 0,different numerologies μ0 to 5 allow for 1, 2, 4, 8, 16, and 32 slots,respectively, per subframe. For slot configuration 1, differentnumerologies 0 to 2 allow for 2, 4, and 8 slots, respectively, persubframe. Accordingly, for slot configuration 0 and numerology μ, thereare 14 symbols/slot and 2^(μ) slots/subframe. The subcarrier spacing andsymbol length/duration are a function of the numerology. The subcarrierspacing may be equal to 2^(μ)*15 kKz, where μ is the numerology 0 to 5.As such, the numerology μ=0 has a subcarrier spacing of 15 kHz and thenumerology μ=5 has a subcarrier spacing of 480 kHz. The symbollength/duration is inversely related to the subcarrier spacing. FIGS.2A-2D provide an example of slot configuration 0 with 14 symbols perslot and numerology μ=0 with 1 slot per subframe. The subcarrier spacingis 15 kHz and symbol duration is approximately 66.7 μs.

A resource grid may be used to represent the frame structure. Each timeslot includes a resource block (RB) (also referred to as physical RBs(PRBs)) that extends 12 consecutive subcarriers. The resource grid isdivided into multiple resource elements (REs). The number of bitscarried by each RE depends on the modulation scheme.

As illustrated in FIG. 2A, some of the REs carry reference (pilot)signals (RS) for the UE. The RS may include demodulation RS (DM-RS)(indicated as R_(x) for one particular configuration, where 100 x is theport number, but other DM-RS configurations are possible) and channelstate information reference signals (CSI-RS) for channel estimation atthe UE. The RS may also include beam measurement RS (BRS), beamrefinement RS (BRRS), and phase tracking RS (PT-RS).

FIG. 2B illustrates an example of various DL channels within a subframeof a frame. The physical downlink control channel (PDCCH) carries DCIwithin one or more control channel elements (CCEs), each CCE includingnine RE groups (REGs), each REG including four consecutive REs in anOFDM symbol. A primary synchronization signal (PSS) may be within symbol2 of particular subframes of a frame. The PSS is used by a UE 104 todetermine subframe/symbol timing and a physical layer identity. Asecondary synchronization signal (SSS) may be within symbol 4 ofparticular subframes of a frame. The SSS is used by a UE to determine aphysical layer cell identity group number and radio frame timing. Basedon the physical layer identity and the physical layer cell identitygroup number, the UE can determine a physical cell identifier (PCI).Based on the PCI, the UE can determine the locations of theaforementioned DM-RS. The physical broadcast channel (PBCH), whichcarries a master information block (MIB), may be logically grouped withthe PSS and SSS to form a synchronization signal (SS)/PBCH block. TheMIB provides a number of RBs in the system bandwidth and a system framenumber (SFN). The physical downlink shared channel (PDSCH) carries userdata, broadcast system information not transmitted through the PBCH suchas system information blocks (SIBs), and paging messages.

As illustrated in FIG. 2C, some of the REs carry DM-RS (indicated as Rfor one particular configuration, but other DM-RS configurations arepossible) for channel estimation at the base station. The UE maytransmit DM-RS for the physical uplink control channel (PUCCH) and DM-RSfor the physical uplink shared channel (PUSCH). The PUSCH DM-RS may betransmitted in the first one or two symbols of the PUSCH. The PUCCHDM-RS may be transmitted in different configurations depending onwhether short or long PUCCHs are transmitted and depending on theparticular PUCCH format used. Although not shown, the UE may transmitsounding reference signals (SRS). The SRS may be used by a base stationfor channel quality estimation to enable frequency-dependent schedulingon the UL.

FIG. 2D illustrates an example of various UL channels within a subframeof a frame. The PUCCH may be located as indicated in one configuration.The PUCCH carries uplink control information (UCI), such as schedulingrequests, a channel quality indicator (CQI), a precoding matrixindicator (PMI), a rank indicator (RI), and HARQ ACK/NACK feedback. ThePUSCH carries data, and may additionally be used to carry a bufferstatus report (BSR), a power headroom report (PHR), and/or UCI.

FIG. 3 is a block diagram of a base station 310 in communication with aUE 350 in an access network. In the DL, IP packets from the EPC 160 maybe provided to a controller/processor 375. The controller/processor 375implements layer 3 and layer 2 functionality. Layer 3 includes a radioresource control (RRC) layer, and layer 2 includes a service dataadaptation protocol (SDAP) layer, a packet data convergence protocol(PDCP) layer, a radio link control (RLC) layer, and a medium accesscontrol (MAC) layer. The controller/processor 375 provides RRC layerfunctionality associated with broadcasting of system information (e.g.,MIB, SIBs), RRC connection control (e.g., RRC connection paging, RRCconnection establishment, RRC connection modification, and RRCconnection release), inter radio access technology (RAT) mobility, andmeasurement configuration for UE measurement reporting; PDCP layerfunctionality associated with header compression/decompression, security(ciphering, deciphering, integrity protection, integrity verification),and handover support functions; RLC layer functionality associated withthe transfer of upper layer packet data units (PDUs), error correctionthrough ARQ, concatenation, segmentation, and reassembly of RLC servicedata units (SDUs), re-segmentation of RLC data PDUs, and reordering ofRLC data PDUs; and MAC layer functionality associated with mappingbetween logical channels and transport channels, multiplexing of MACSDUs onto transport blocks (TBs), demultiplexing of MAC SDUs from TBs,scheduling information reporting, error correction through HARQ,priority handling, and logical channel prioritization.

The transmit (TX) processor 316 and the receive (RX) processor 370implement layer 1 functionality associated with various signalprocessing functions. Layer 1, which includes a physical (PHY) layer,may include error detection on the transport channels, forward errorcorrection (FEC) coding/decoding of the transport channels,interleaving, rate matching, mapping onto physical channels,modulation/demodulation of physical channels, and MIMO antennaprocessing. The TX processor 316 handles mapping to signalconstellations based on various modulation schemes (e.g., binaryphase-shift keying (BPSK), quadrature phase-shift keying (QPSK),M-phase-shift keying (M-PSK), M-quadrature amplitude modulation(M-QAM)). The coded and modulated symbols may then be split intoparallel streams. Each stream may then be mapped to an OFDM subcarrier,multiplexed with a reference signal (e.g., pilot) in the time and/orfrequency domain, and then combined together using an Inverse FastFourier Transform (IFFT) to produce a physical channel carrying a timedomain OFDM symbol stream. The OFDM stream is spatially precoded toproduce multiple spatial streams. Channel estimates from a channelestimator 374 may be used to determine the coding and modulation scheme,as well as for spatial processing. The channel estimate may be derivedfrom a reference signal and/or channel condition feedback transmitted bythe UE 350. Each spatial stream may then be provided to a differentantenna 320 via a separate transmitter 318TX. Each transmitter 318TX maymodulate an RF carrier with a respective spatial stream fortransmission.

At the UE 350, each receiver 354RX receives a signal through itsrespective antenna 352. Each receiver 354RX recovers informationmodulated onto an RF carrier and provides the information to the receive(RX) processor 356. The TX processor 368 and the RX processor 356implement layer 1 functionality associated with various signalprocessing functions. The RX processor 356 may perform spatialprocessing on the information to recover any spatial streams destinedfor the UE 350. If multiple spatial streams are destined for the UE 350,they may be combined by the RX processor 356 into a single OFDM symbolstream. The RX processor 356 then converts the OFDM symbol stream fromthe time-domain to the frequency domain using a Fast Fourier Transform(FFT). The frequency domain signal comprises a separate OFDM symbolstream for each subcarrier of the OFDM signal. The symbols on eachsubcarrier, and the reference signal, are recovered and demodulated bydetermining the most likely signal constellation points transmitted bythe base station 310. These soft decisions may be based on channelestimates computed by the channel estimator 358. The soft decisions arethen decoded and deinterleaved to recover the data and control signalsthat were originally transmitted by the base station 310 on the physicalchannel. The data and control signals are then provided to thecontroller/processor 359, which implements layer 3 and layer 2functionality.

The controller/processor 359 can be associated with a memory 360 thatstores program codes and data. The memory 360 may be referred to as acomputer-readable medium. In the UL, the controller/processor 359provides demultiplexing between transport and logical channels, packetreassembly, deciphering, header decompression, and control signalprocessing to recover IP packets from the EPC 160. Thecontroller/processor 359 is also responsible for error detection usingan ACK and/or NACK protocol to support HARQ operations.

Similar to the functionality described in connection with the DLtransmission by the base station 310, the controller/processor 359provides RRC layer functionality associated with system information(e.g., MIB, SIBs) acquisition, RRC connections, and measurementreporting; PDCP layer functionality associated with headercompression/decompression, and security (ciphering, deciphering,integrity protection, integrity verification); RLC layer functionalityassociated with the transfer of upper layer PDUs, error correctionthrough ARQ, concatenation, segmentation, and reassembly of RLC SDUs,re-segmentation of RLC data PDUs, and reordering of RLC data PDUs; andMAC layer functionality associated with mapping between logical channelsand transport channels, multiplexing of MAC SDUs onto TBs,demultiplexing of MAC SDUs from TBs, scheduling information reporting,error correction through HARQ, priority handling, and logical channelprioritization.

Channel estimates derived by a channel estimator 358 from a referencesignal or feedback transmitted by the base station 310 may be used bythe TX processor 368 to select the appropriate coding and modulationschemes, and to facilitate spatial processing. The spatial streamsgenerated by the TX processor 368 may be provided to different antenna352 via separate transmitters 354TX. Each transmitter 354TX may modulatean RF carrier with a respective spatial stream for transmission.

The UL transmission is processed at the base station 310 in a mannersimilar to that described in connection with the receiver function atthe UE 350. Each receiver 318RX receives a signal through its respectiveantenna 320. Each receiver 318RX recovers information modulated onto anRF carrier and provides the information to a RX processor 370.

The controller/processor 375 can be associated with a memory 376 thatstores program codes and data. The memory 376 may be referred to as acomputer-readable medium. In the UL, the controller/processor 375provides demultiplexing between transport and logical channels, packetreassembly, deciphering, header decompression, control signal processingto recover IP packets from the UE 350. IP packets from thecontroller/processor 375 may be provided to the EPC 160. Thecontroller/processor 375 is also responsible for error detection usingan ACK and/or NACK protocol to support HARQ operations.

At least one of the TX processor 368, the RX processor 356, and thecontroller/processor 359 may be configured to perform aspects inconnection with 199 of FIG. 1.

At least one of the TX processor 316, the RX processor 370, and thecontroller/processor 375 may be configured to perform aspects inconnection with 198 of FIG. 1.

A communication system, such as a 5G NR communication system, may havesome base stations that have a limited coverage area. The limitedcoverage area may be due to environmental factors, such as a basestation being in a dense urban environment, signals being blocked byterrain, among other examples. Relay nodes may provide additionalcoverage in the communication system that may not be provided by thebase station. Relay nodes relay a signal from the base station and mayexpand or enhance the serving area of the base station by relayingcommunication between one or more UEs and the base station. Relay nodesmay be used to fill coverage gaps of the serving area of the basestation, for example, without installation of an additional basestation. A relay node may have a connection to a base station, which maybe referred to as a donor base station. As an example, a base stationproviding coverage for a relay may be referred to as a donor gNB. Onceconnected, a relay node may relay the signal from the donor basestation, thereby expanding or improving the coverage of the basestation. Relay nodes may be stationary. In some examples, a relay nodemay be mobile and may move within the coverage area of the base stationor may move out of the coverage area of the base station. For mobilerelays, a relay may be located in a vehicle, such as a bus, taxi, train,or car, among others. The mobile relay may provide coverage toneighboring UEs, which can be in the vehicle itself or in the vicinityof the vehicle.

FIG. 4 is a diagram illustrating an example of a base station 402, a UE406, and a mobile relay 404 in an access network 400 in accordance tocertain aspects of the disclosure. In some examples, an access networkincluding mobile relays may be referred to as a fleet network, or aFleetNet system. The example diagram 400 of FIG. 4 includes a basestation 402 (e.g., gNB), mobile relays 404, and a UE 406. The mobilerelay 404 may be connected to the base station 402, such that the basestation 402 is a donor base station (e.g., donor gNB). The radio link,e.g., link 408, between the mobile relay 404 and the base station 402may be an Uu link 408, such as based on Uu NR. The link between themobile relay 404 and the UE may include a Uu link 408 or a PC5 link 410,such as based on Uu NR and/or PC5 NR. In some aspects, neighboringmobile relays 404 may be configured to communicate with each other via alink 410 based on PC5. A Uu interface is the radio interface between amobile device (e.g., UE) and the radio access network. For example, a Uuinterface may include an interface between a UE and a base station forcommunication between the UE and the network. The Uu interface mayinclude both the user plane and the control plane signaling and/or datastreams. In some aspects, messages for the Uu interface may be carriedover a D2D link, such as the PC5 link 410. Therefore, the PC5 link 410may be configured to carry the signaling and/or messages for the Uuinterface in order to provide communication between the UE 406 and thebase station 402. PC5 is an example, of a D2D link directly betweendevices that supports communication directly between the devices withoutpassing the communication through a base station. Such a D2D link maysupport sidelink communication between the two devices.

The mobile nature of mobile relays 404 may lead to unique challenges ina communication system in which the UEs 406 use mobile relays 404 tocommunicate with the network, e.g., with base station 402.

In some examples, a UE 406 may need to perform frequent reselections toa new mobile relay 404. Aspects presented herein may help the UE 406 tosearch for mobile relays 404 and/or select mobile relays 404 in a moreefficient manner.

A base station 402 may maintain neighbor lists that contain a list ofneighboring cells. There can be different types of neighbor lists. Forexample, an internal neighbor list may be maintained by the base station402 with a list of neighboring cells for a particular served cell. Abroadcast neighbor list may be broadcast by the base station 402 in thesystem information block (SIB) for use by UEs 406 in an idle mode. Forintra-frequency and inter-frequency cells, the serving cell may notprovide an explicit neighbor list and may provide carrier frequencyinformation and bandwidth information only. However, providing anexplicit neighbor list (e.g., a list of Physical Cell Identities (PCIs))per carrier frequency enables the network to configure cell-specificreselection parameters that can be specified on a per-cell basis. Thisincludes a Q-offset value that biases the reselection either for oragainst the cell relative to the other cells by modifying its rank.Cells can also be explicitly called out as blacklisted to help a UE 406avoid reselection to such cells. In another example, a dedicatedneighbor list may be sent by the base station 402 to a UE 406, e.g., ina connected mode with the base station 402. The dedicated neighbor listmay include a list of PCI per carrier frequency, e.g., having anoptional offset for each PCI. Providing the list of PCIs and associatedoffsets to the UE 406 may help the UE 406 to perform measurements onneighbor cells more quickly.

Base stations 402 may often be stationary, so that the list ofneighboring cells of neighbor base stations may be relatively fixed.Thus, the neighboring cells that the UE 406 is expected to detect forpotential handovers may also be relatively fixed. As such, the basestation 402 might not send an explicit neighbor list to a UE 406 in anidle mode. However, in wireless communication systems that includemobile relays 404 that provide service to mobile UEs 406, theneighboring relays for the UE 406 may continually change.

A UE 406 in an idle mode may select a best cell (whether for a basestation or a mobile relay) based on a scanning procedure performed bythe UE 406. A UE 406 camped on a mobile relay 404 may perform frequentreselections to a new mobile relay 404 due to the mobility of the mobilerelay 404 and/or the UE 406. The frequent reselections may expendconsiderable resources at the UE 406. As presented herein, a basestation 402 may provide a neighbor list to a UE 406 in idle mode andcamped on a mobile relay 404 to assist in reducing the amount ofreselections performed by the UE 406 and/or improving the efficiency ofthe reselection performed by the UE 406. A base station 402 providing aneighbor list to a UE 406 in a connected mode may also assist inensuring successful handovers for the UE 406. Aspects presented hereinmay enable a UE 406 camped on a mobile relay 404 to identify neighboringrelays based on assistance information provided by a base station 402.The base station 402 may update the assistance information, such as aneighbor list, sent to the UE 406 based on the UE's location and/or thelocations of the mobile relays 404.

Each cell served by a base station 402 may be dimensioned according tothe number of UEs that the cell is expected to serve, and/or based onthe density of the area within its coverage area in terms of population.However, in communication systems that include mobile relays 404, thenumber of users served by a mobile relay 404, and the number of mobilerelays served by a base station 402, might not be accurately predicteddue to the mobility of the mobile relays 404 relative to a base station402 and due to movement of the mobile relays 404 and the UEs 406relative to each other. Aspects presented herein enable the load of themobile relay 404 and/or the donor base station, e.g., base station 402,to be taken into account prior to a UE 406, in idle mode, reselectingfrom one mobile relay 404 to another, prior to a mobile relay 404reselecting from one donor base station to another donor base station,prior to a donor base station handing over a mobile relay to anotherdonor base station, or prior to a UE 406, in a connected mode, beinghanded over to another mobile relay 404.

Each cell may be associated with a particular PCI. For example, cellswith a same PCI may be distinguished by an unique Cell GlobalIdentifiers (NCGI) of a respective cell. The PCI may be carried byPSS/SSS in a SSB block from the cell. The PCI may be used to determinescrambling sequence of a physical signal or physical channelstransmitted by the cell. As an example, any of a Physical BroadcastChannel (PBCH), a PDCCH (e.g., PDCCH CoreSet0), a cell-specific PDSCHtransmission, etc. from the cell may be scrambled based on the PCI forthe cell. For example, the PCI may be used as a scrambling seed forscrambling the channels. Other channels may be scrambled based onanother scrambling seed. The number of possible PCI values may belimited, and the PCI may be reused across a network. In some examples,PCI values may be reused by multiple geographically separated cells in anetwork.

However, a mobile relay 404 having a particular PCI may come intoproximity with another cell having the same PCI. As signals from themobile relay node 404 and the other cell may both be scrambled based onthe same PCI, a UE 406 receiving the signals may not be able tocorrectly identify the source of the signal, e.g., may be unable todifferentiate between a signal from the mobile relay 404 and a signalfrom the other cell. The use of a same PCI value by the mobile relay 404and another cell within proximity of the mobile relay may be referred toas a PCI collision. PCI collisions may lead to issues with timingsynchronization and channel estimation, and may further cause decodingfailures for data traffic transmitted from at least one of these twoneighboring cells.

Mobile relays 404 may have an output power that is significantly lowerthan the output power of a base station 402. The lower output power ofthe mobile relays 404 may lead to more frequent handovers than for abase station 402.

FIG. 5 is a diagram illustrating an example communication system 500including a base station 402, UE 406, and a mobile relay 404 in anaccess network in accordance with certain aspects of the disclosure.Similar reference numbers to FIG. 4 are used to designate similaraspects of FIG. 5. However, the communication system 500 furtherincludes a relay discovery assistance entity 502 and may include agateway mobile location center (GMLC) 504. Once the UE 406 is connectedto the network via the mobile relay 404, both the UE 406 and mobilerelay 404 may periodically report their position to a network entity.

In some aspects, the network entity may be configured to act as anapplication function (AF) and may send a request to the GMLC 504 toobtain the location of the mobile relay 404 and the UE 406. Afterreceipt of the location information of the mobile relay 404 and the UE406 from the GMLC 504, the network entity may determine the relativeproximity between the UE 406 and the mobile relay 404.

In some aspects, the network entity may be a relay discovery assistanceentity 502 that is separate from the base station 402, while having aninterface 506 with the base station 402. However, the disclosure is notintended to be limited to the aspects disclosed herein.

In some aspects, the base station 402 may be configured to be thenetwork entity. The base station may comprise the relay discoveryassistance entity 502 that provides assistance information to the UE foruse in selecting a mobile relay.

In some aspects, the mobile relay 404 and UE 406 may be configured toprovide their position to the network entity (e.g., relay discoveryassistance entity 502) by way of the base station 402.

In some examples, such as when the base station 402 acts as the networkentity, the mobile relay 404 and the UE 406 may provide their positiondirectly to the base station 402, such as illustrated in FIG. 6. Forexample, mobile relay 404 may provide its location to the network entity(e.g., relay discovery assistance entity 602) via link 604, while the UE406 may provide its location to the network entity (e.g., relaydiscovery assistance entity 602) via link 606. In aspects, where thebase station 402 is the network entity, the mobile relay 404 may provideits location to the base station via link 604, while the UE 406 mayprovide its location to the base station by transmitting it directly tothe base station via link 606 or by way of the mobile relay 404.However, in some aspects as shown in FIG. 5, the mobile relay 404 and UE406 may be configured to provide their position directly to anothernetwork entity (e.g., to a GMLC 504) from which the relay discoveryassistance entity 502 receives the location information.

FIGS. 5 and 6 only illustrate a single UE 406 and a single mobile relay404 to illustrate the principles herein. However, the aspects presentedherein may be employed for one or more UEs and one or more mobilerelays.

Upon receipt of the location information of the one or more mobilerelays 404 and the one or more UEs 406, the network entity (e.g., basestation 402 or relay discovery assistance entity 502) may utilize thelocation information to determine which mobile relays are within thevicinity of the one or more UEs 406. The network entity (e.g., basestation 402 or relay discovery assistance entity 502) may generateassistance information related to the other relays that are within thevicinity of the one or more UEs 406. In some aspects, the network entity(e.g., base station 402 or relay discovery assistance entity 502) maysend the assistance information to a UE 406 via dedicated signaling, ormay broadcast the assistance information in SIB. The assistanceinformation may help a UE 406 to discover mobile relay(s) within thevicinity of the UE.

FIG. 7 illustrates an example communication flow 700 between a UE 706, arelay discovery assistance entity 702, and a mobile relay 704. The relaydiscovery assistance entity 702 may include a component of a basestation or may correspond to a base station. The relay discoveryassistance entity 702 may correspond to a core network entity, and mayhave an interface to a base station. As described in connection withFIGS. 5 and 6, the relay discovery assistance entity 702 may receivelocation information 710 from the UE 706 and location information 708from the mobile relay 704. Although only a single UE 706 and a singlemobile relay 704 are used to illustrate the concepts in FIG. 7, theaspects may be applied for multiple UEs and multiple mobile relays.Therefore, the relay discovery assistance entity 702 may receivelocation information for multiple UEs 706. The relay discoveryassistance entity 702 may receive location information for multiplemobile relays 704. As described in connection with FIG. 5, the relaydiscovery assistance entity 702 may receive the location informationfrom another network entity, such as from a GMLC. The relay discoveryassistance entity 702 may receive the location updates directly from theUE 706 and/or the mobile relay 704, as described in the example in FIG.6. As illustrated at 712, the relay discovery assistance entity 702 maydetermine a distance between the UE 706 and the mobile relay 704, andmay similarly determine a distance between multiple UEs and each of oneor more mobile relays. The relay discovery assistance entity 702 may usethe determination, at 712, to identify mobile relays within a certainarea or a certain range of the UE(s). The relay discovery assistanceentity 702 may then send assistance information 714 to the UE 706.

The relay discovery assistance entity 702 may send the assistanceinformation 714 to the UE via dedicated signaling. If there are multipleUEs, the relay discovery assistance entity 702 may send assistanceinformation 714 to each of the UEs in dedicated signaling for therespective UE. Alternately, the assistance information 714 may bebroadcast by a base station in system information, such as a SIB.

The assistance information 714 may be sent to the UE in a differentfrequency band than other service for the UE, e.g., user data transferfor the UE. Therefore, the assistance information 714 may be sent in adifferent frequency band than other communication from the base stationto the UE. As the assistance information may not need a high data rate,the assistance information may be sent with a lower bit rate that datafor the UE, e.g., in order to save radio resources.

The relay discovery assistance entity 702, or another network entity,may restrict the list of available relays that is provided to the UE.The restricted list may indicate that the UE is restricted to camping onthe mobile relays on the list. For example, the restricted list may beused to minimize the number of reselections performed by the UE. Therelay discovery assistance entity 702 can send the restricted listinformation to the UE in dedicated signaling to the UE. The relaydiscovery assistance entity 702 may provide the restricted list to theUE in response to a request 713 from the UE. The information may be sentin system information. For example, the restricted list, or otherassistance information, may be provided to the UE via an on-demand SIBthat is transmitted in response to a request 713 from the UE. Therestricted list may include information that is customized to the UEthat requested the restricted list. Similarly, other assistanceinformation that is transmitted to the UE may be customized to the UE.

The UE 706 may use the assistance information 714, provided by the relaydiscovery assistance entity 702, to perform discovery for mobile relays,at 716. The UE 706 may use the assistance information to monitor forsignals from mobile relays.

The UE 706 may fall back to a base station when the UE does not find anyof the relays indicated in the list, e.g., a restricted list provided bythe relay discovery assistance entity 702. The ability to fallback to aconnection with a base station may help to avoid having the UE 706 enteran out-of-service state if the UE 706 is unable to discover any of themobile relays indicated by the network.

In some aspects, the UE 706 may use direct discovery over a PC5interface to discover mobile relays on which the UE can camp. Forexample, the mobile relay 704 may broadcast an ID 722 over PC5 with PCIinformation. As an example, the mobile relay 704 may broadcast a shortID of approximately 2-3 bytes from which the UE can deduce the PCI ofthe mobile relay 704. Then the UE would acquire the PCI for the relaysin proximity. The mobile relay 704 may generate the identifier at 720,based on the PCI for the mobile relay 704. The UE 706 may use thebroadcast ID 722 to determine the PCI for the mobile relay 704, at 724.As illustrated at 726, the UE 706 may report the discovered mobilerelays to a network entity (e.g., a base station or other relaydiscovery assistance entity 702). For example, the report of discoveredmobile relays may assist a donor base station in maintaining a current,accurate list of neighboring mobile relays.

In some aspects load information may be advertised. The load informationmay be taken into account before camping decisions involving a mobilerelay are made. A mobile relay 704 may broadcast an indication 730 ofwhether the mobile relay 704 is capable of accepting additional UEs. Themobile relay 704 may determine, at 728, whether the mobile relay iscapable of supporting an additional UE. The indication 730 may beprovided, e.g., over an Uu interface in a SIB (such as a new SIB or amodification of an existing SIB). The indication 730 may be provided,e.g., over a PC5 interface. The indication 730 may indicate whether ornot the mobile relay is accepting new UEs.

FIG. 7B illustrates an example continued communication flow 700 betweenthe

UE, the relay discovery assistance entity 702, and the mobile relay 704.The UE 706 can use the above-described indication from the mobile relayinto account when deciding whether to camp on a particular mobile relay,e.g., as illustrated at 732. In some aspects, the UE may place relaysthat cannot accept new UEs as lowest priority location in the list ofcandidate relays on which the UE may camp, e.g., as illustrated at 734.In some aspects, the UE may remove the mobile relay from the list ofcandidate relay when the indication indicates that the mobile relay isnot accepting new UEs.

Similarly, a donor base station may broadcast an indication 738 ofwhether the donor base station can accept new mobile relays. In anexample in which the relay discovery assistance entity 702 correspondsto a base station, the base station may determine, at 736, whether thebase station is capable of supporting additional mobile relays. Then,the base station may transmit indication 738, e.g., broadcast in systeminformation such as a SIB. The mobile relay 704 may receive theindication 738 and may use information, at 740, when deciding whether tocamp on a donor base station. For example, if the indication indicatesthat the base station is not accepting, or is not capable of accepting,additional mobile relays, the mobile relay may determine not to camp onthe base station. The mobile relay be move the base station to a lowest,or lower, priority level on a candidate base station list, asillustrated at 742. In some aspects, the mobile relay may remove thebase station from the candidate base station list when the indicationindicates that the base station is not accepting new mobile relays.

FIG. 8 is a flowchart 800 of a method of wireless communication. Themethod may be performed by a network entity or a component of a networkentity (e.g., the core network 190 or the base station 102,180, 310,402, 1850, 2050; the apparatus 1602/1602′; the processing system 1714,which may include the memory 376 and which may be the entire basestation 310 or a component of the base station 310, such as the TXprocessor 316, the RX processor 370, and/or the controller/processor375). The network entity may correspond to the relay discoveryassistance entity 502/602 or the base station 402, as discussed above inconnection with FIG. 5 or FIG. 6. According to various aspects, one ormore of the illustrated operations of the method 800 may be omitted,transposed, and/or contemporaneously performed. Optional aspects areillustrated with a dashed line. The method may enable a network entityto provide assistance information to at least one UE in an area thatidentifies at least one mobile relay within the vicinity of the at leastone UE.

At 802, the network entity may receive first location information forone or more UEs. For example, 802 may be performed by first locationcomponent 1606 of apparatus 1602. In some aspects, for example as shownin FIG. 6, the network entity may receive the location information forthe one or more UEs directly form the one or more UEs.

At 804, the network entity may receive second location information forone or more mobile relays. For example, 804 may be performed by secondlocation component 1608 of apparatus 1602. In some aspects, the networkentity may receive the first location information for the one or moreUEs and the second location information for the one or more mobilerelays from another network entity.

At 806, the network entity may determine a distance between the one ormore UEs and each of the one or more mobile relays. For example, 806 maybe performed by distance component 1610 of apparatus 1602. The networkentity may determine the distance between the one or more UEs and eachof the one or more mobile relays, based on the first locationinformation received for the one or more UEs, and the second locationinformation received for the one or more mobile relays.

At 808, the network entity may send assistance information to at leastone of the one or more UEs in an area. For example, 808 may be performedby assistance information component 1612 of apparatus 1602. Theassistance information may identify at least one mobile relay of the oneor more mobile relays based on the determined distance between the oneor more UEs and the at least one mobile relay. The area in which the oneor more UEs is may be the serving cell area of the serving cell. In someaspects, the network entity sends the assistance information to the atleast one of the one or more UEs in dedicated signaling for the at leastone of the one or more UEs. In some aspects, the dedicated signaling maycomprise a RRC message for the at least one of the one or more UEs. Insome aspects, the network entity may broadcast the assistanceinformation in system information. The communication for the one or moreUEs may be transmitted using a first frequency band, while theassistance information may be transmitted to the at least one of the oneor more UEs using a second frequency band. In some aspects, the secondfrequency band is different than the first frequency band. In someaspects, transmission of the assistance information may not require ahigh data rate, such that it may be sent in a different frequency band(e.g., second frequency band) having a lower bit rate, in order to saveradio resources. In some aspects, the assistance information may includea temporarily restricted list of mobile relays. For example, the networkentity may restrict the list of mobile relays provided and indicate thatthe at least one of the one or more UEs is only allowed to camp on therestricted list of mobile relays. The network entity providing arestricted list of mobile relays may minimize the number of reselectionsperformed by the at least one of the one or more UEs.

In some aspects, for example, at 810, the network entity may receive arequest from a UE. For example, 810 may be performed by receptioncomponent 1604 of apparatus 1602. In some aspects, the assistanceinformation may be sent to the UE in response to the request from theUE. In some aspects, the assistance information may be sent to the UEvia on-demand SIB, in response to the request from the UE. Theassistance information may be customized to the UE which has submittedthe request to the network entity. The network entity, in some aspects,may correspond to the relay discovery assistance entity 502 of FIG. 5 orthe relay discovery assistance entity 602 of FIG. 6. In some aspects,the network entity may correspond to the base station 402, as discussedabove in FIG. 5.

FIG. 9 is a flowchart 900 of a method of wireless communication. Themethod may be performed by a UE or a component of a UE (e.g., the UE104, 350, 406, 706, 1660, 2060; the apparatus 1802/1802; the processingsystem 1914, which may include the memory 360 and which may be theentire UE 350 or a component of the UE 350, such as the TX processor368, the RX processor 356, and/or the controller/processor 359).According to various aspects, one or more of the illustrated operationsof the method 900 may be omitted, transposed, and/or contemporaneouslyperformed. Optional aspects are illustrated with a dashed line. Themethod may enable a UE to discover a mobile relay within the vicinity ofthe UE based on assistance information provided by a network entity.

At 902, the UE may provide location information to a base station. Forexample, 902 may be performed by location component 1806 of apparatus1802. The location information provided to the base station may berelated to the UE.

At 904, the UE may receive, from a network entity, assistanceinformation that may identify at least one mobile relay within adistance of the UE. For example, 904 may be performed by assistanceinformation component 1808 of apparatus 1802. In some aspects, the UEmay provide the location information for the UE to the network entity.While in some aspects, the UE may provide the location information forthe UE to another network entity. The UE may receive the assistanceinformation from the network entity in dedicated signaling for the UE.In some aspects, the dedicated signaling may comprise a RRC message forthe UE. In some aspects, the UE may receive the assistance informationin broadcast system information. In some aspects, the UE may receivedata using a first frequency band, such that the UE receives theassistance information using a second frequency band. The secondfrequency band may be different than the first frequency band. In someaspects, transmission of the assistance information may not require ahigh data rate, such that it may be sent in a different frequency band(e.g., second frequency band) having a lower bit rate, in order to saveradio resources. In some aspects, the assistance information may includea restricted list of mobile relays. The restricted list of mobile relaysmay indicate that the UE is only allowed to camp on the restricted listof mobile relays. The network entity providing the restricted list ofmobile relays may minimize the number of reselections performed by theUE.

In some aspects, for example, at 906, the UE may perform discovery for amobile relay. For example, 906 may be performed by discovery component1810 of apparatus 1802. The UE may perform discovery for the mobilerelay based on the assistance information provided from the networkentity.

In some aspects, for example, at 908, the UE may select a mobile relayfor relaying communication from the UE to a base station. For example,908 may be performed by selection component 1812 of apparatus 1802. TheUE may select the mobile relay for relaying communication from the UE tothe base station based on the assistance information received from thenetwork entity. In some aspects, the UE selecting the mobile relay mayallow the UE to handover from one mobile relay to another.

In some aspects, for example, at 910, the UE may communicate with thebase station without the mobile relay when the UE is unable to discoverthe mobile relay, including the at least one mobile relay identified inthe assistance information. For example, 910 may be performed bycommunication component 1814 of apparatus 1802. The UE communicatingwith the base station without the mobile relay may assist in having theUE avoid entering an out-of-service state or experiencing radio linkfailure, such that the UE may fallback or revert to communicating withthe base station.

In some aspects, for example, at 912, the UE may send a request to thenetwork entity. For example, 912 may be performed by request component1816 of apparatus 1802. The UE may receive the assistance information inresponse to the request sent to the network entity. In some aspects, theassistance information may be provided via on-demand SIB, in response tothe request from the UE. The assistance information may be customized tothe UE which has submitted the request to the network entity. Thenetwork entity, in some aspects, may correspond to the relay discoveryassistance entity 502 of FIG. 5 or the relay discovery assistance entity602 of FIG. 6. In some aspects, the network entity may correspond to thebase station 402, as discussed above in FIG. 5.

FIG. 10 is a flowchart 1000 of a method of wireless communication. Themethod may be performed by a relay device (e.g., 107, 404, 704, 1650,1860; the apparatus 2002/2002′; the processing system 2114). Accordingto various aspects, one or more of the illustrated operations of themethod 1000 may be omitted, transposed, and/or contemporaneouslyperformed. The method may enable a relay device to generate anidentifier that allows a UE to derive the physical cell identity (PCI)for the relay device.

At 1002, the relay device may generate an identifier. For example, 1002may be performed by identifier component 2006 of apparatus 2002. Theidentifier may enable a UE to derive the PCI for the relay device. Therelay device may correspond to the mobile relay 404.

At 1004, the relay device may broadcast the identifier. For example,1004 may be performed by transmission component 2016 of apparatus 2002.In some aspects, the relay device may broadcast the identifier usingdevice-to-device communication (e.g., PC5). PC5 is one example ofdevice-to-device communication, whereby device-to-device communicationoccurs via the PC5 interface, and the disclosure is not intended to belimited to the aspects disclosed herein. In some aspects, the identifiermay be a short identifier (e.g., 2-3 bytes) that is broadcast usingdevice-to-device communication. The short identifier may be longer orshorter than 2-3 bytes, and is not intended to be limited to the aspectsdisclosed herein. The UE may utilize the short identifier to deduce thePCI of the relay.

FIG. 11 is a flowchart 1100 of a method of wireless communication. Themethod may be performed by a UE or a component of a UE (e.g., the UE104, 350, 406, 706, 1660, 2060; the apparatus 1802/1802; the processingsystem 1914, which may include the memory 360 and which may be theentire UE 350 or a component of the UE 350, such as the TX processor368, the RX processor 356, and/or the controller/processor 359).According to various aspects, one or more of the illustrated operationsof the method 1100 may be omitted, transposed, and/or contemporaneouslyperformed. The method may enable a UE to determine the PCI of a mobilerelay.

At 1102, the UE may receive an identifier from a mobile relay. Forexample, 1102 may be performed by identifier component 1818 of apparatus1802. The identifier from the mobile relay may indicate a PCI for themobile relay.

At 1104, the UE may determine the PCI of the mobile relay from thereceived identifier. For example, 1104 may be performed by PCI component1820 of apparatus 1802. In some aspects, the UE may receive theidentifier in a broadcast from the mobile relay. For example, thebroadcast from the mobile relay may be based on PC5 communication. Insome aspects, the identifier may be a short identifier (e.g., 2-3 bytes)that is broadcast using device-to-device communication (e.g., PC5communication). The short identifier may be longer or shorter than 2-3bytes, and is not intended to be limited to the aspects disclosedherein. The UE may utilize the short identifier to deduce the PCI of themobile relay.

In some aspects, for example, at 1106, the UE may report the PCI of themobile relay to a network entity. For example, 1106 may be performed byreport component 1822 of apparatus 1802. The UE may report the PCI ofthe mobile relay to the network entity in order to assist a donor basestation to maintain or update a list of neighboring relays. In someaspects, the network entity may comprise the base station or anothernetwork entity.

FIG. 12 is a flowchart 1200 of a method of wireless communication. Themethod may be performed by a relay device (e.g., 107, 404, 704, 1650,1860; the apparatus 2002/2002′; the processing system 2114). Accordingto various aspects, one or more of the illustrated operations of themethod 1200 may be omitted, transposed, and/or contemporaneouslyperformed. The method may enable a mobile relay device to indicatewhether the additional UEs may be supported.

At 1202, the mobile relay device may determine if the mobile relaydevice is capable of supporting an additional UE. For example, 1202 maybe performed by determination component 2008 of apparatus 2002. Themobile relay device may determine if the mobile relay device is capableof supporting the additional UE based on a current load of the mobilerelay device. For example, the mobile relay device may not havesufficient available resources to support the additional UE.

At 1204, the mobile relay device may transmit an indication indicatingwhether the mobile relay device is capable of accepting the additionalUE. For example, 1204 may be performed by transmission component 2016 ofapparatus 2002. In some aspects, the mobile relay device may broadcastthe indication. The mobile relay device may broadcast the indication assystem information using an Uu interface. In some aspects, the mobilerelay device may broadcast the indication using device-to-devicecommunication (e.g., PC5).

FIG. 13 is a flowchart 1300 of a method of wireless communication. Themethod may be performed by a UE or a component of a UE (e.g., the UE104, 350, 406, 706, 1660, 2060; the apparatus 1802/1802; the processingsystem 1914, which may include the memory 360 and which may be theentire UE 350 or a component of the UE 350, such as the TX processor368, the RX processor 356, and/or the controller/processor 359).According to various aspects, one or more of the illustrated operationsof the method 1300 may be omitted, transposed, and/or contemporaneouslyperformed. The method may enable a UE to select a relay based on thecurrent load of the relay.

At 1302, the UE may receive an indication from a mobile relay indicatingwhether the mobile relay is accepting an additional UE. For example,1302 may be performed by indication component 1824 of apparatus 1802. Insome aspects, the UE may receive the indication in a broadcast from themobile relay. The UE may receive the indication as system informationbased on a Uu interface. In some aspects, the UE may receive theindication as system information based on device-to-device communication(e.g., PC5).

In some aspects, for example, at 1304, the UE may assign the mobilerelay a reduced priority in a candidate list when the indicationindicates that the mobile relay is not accepting the additional UE. Forexample, 1304 may be performed by priority component 1828 of apparatus1802. In some aspects, the UE may remove the mobile relay from the listof candidate relays when the indication indicates that the mobile relayis not accepting new UEs. In some aspects, the UE may account for theinformation within the indication when deciding which relay to select,and may assign or give mobile relays a lower or lowest priority in thecandidate list on which the UE may camp on, when mobile relays indicatethat they cannot accept additional UEs.

At 1306, the UE may select a relay for communication with a network. Forexample, 1306 may be performed by relay component 1826 of apparatus1802. The UE may select the relay for communication with the networkbased, in part, on the indication from the mobile relay.

FIG. 14 is a flowchart 1400 of a method of wireless communication. Themethod may be performed by a base station or a component of a basestation (e.g., the base station 102, 180, 310, 402, 1850, 2050; theapparatus 1602/1602; the processing system 1714, which may include thememory 376 and which may be the entire base station 310 or a componentof the base station 310, such as the TX processor 316, the RX processor370, and/or the controller/processor 375). According to various aspects,one or more of the illustrated operations of the method 1400 may beomitted, transposed, and/or contemporaneously performed. The method mayenable a base station to indicate whether the base station may supportan additional mobile relay based on the current load of the basestation.

At 1402, the base station may determine if the base station is capableof supporting an additional mobile relay. For example, 1402 may beperformed by determination component 1614 of apparatus 1602. The basestation may determine if the base station is capable of supporting theadditional mobile relay based on a current load of the base station.

At 1404, the base station may transmit an indication whether the basestation is capable of accepting the additional mobile relay. Forexample, 1404 may be performed by transmission component 1616 ofapparatus 1602. In some aspects, the base station may broadcast theindication. For example, the base station may broadcast the indicationin system information. A base station that is configured to acceptmobile relays may be known as a donor base station. In response totransmitting the indication as to whether the base station is capable ofaccepting the additional mobile relay, the mobile relay may take theindication into account when deciding whether to camp on the basestation.

FIG. 15 is a flowchart 1500 of a method of wireless communication. Themethod may be performed by a relay device (e.g., 107, 404, 704, 1650,1860; the apparatus 2002/2002′; the processing system 2114). Accordingto various aspects, one or more of the illustrated operations of themethod 1500 may be omitted, transposed, and/or contemporaneouslyperformed. Optional aspects are illustrated with a dashed line. Themethod may enable a mobile relay device to determine whether or not tocamp on a base station.

At 1502, the mobile relay device may receive an indication from a basestation indicating whether the base station is accepting an additionalmobile relay. For example, 1502 may be performed by indication component2010 of apparatus 2002. In some aspects, the mobile relay device mayreceive the indication as system information broadcast from the basestation.

In some aspects, for example, at 1504, the mobile relay device may givethe base station a reduced priority in a candidate list when theindication indicates that the base station is not accepting theadditional mobile relay. For example, 1504 may be performed by prioritycomponent 2014 of apparatus 2002. In some aspects, the mobile relaydevice may remove the base station from the list of candidate basestations when the indication indicates that the base station is notaccepting new mobile relay devices. In some aspects, the mobile relaydevice may account for the information within the indication whendeciding whether to camp on the base station, and may assign basestations that cannot accept additional mobile relays a lower or lowestpriority in the candidate list.

At 1506, the mobile relay device may determine whether to camp on thebase station. For example, 1506 may be performed by camp component 2012of apparatus 2002. The mobile relay device may determine whether to campon the base station based on the indication from the base station. Abase station that is capable of accepting mobile relays may be known asa donor base station.

FIG. 16 is a conceptual data flow diagram 1600 illustrating the dataflow between different means/components in an example apparatus 1602.The apparatus may be a network entity or a component of a networkentity. The apparatus includes a reception component 1604 that may beconfigured to receive various types of signals/messages and/or otherinformation from other devices, including, for example, the mobile relay1650 or the UE 1660. The apparatus includes a first location component1606 that may receive first location information for one or more UEs,e.g., as described in connection with 802 of FIG. 8. The apparatusincludes a second location component 1608 that may receive secondlocation information for one or more mobile relays, e.g., as describedin connection with 804 of FIG. 8. The apparatus includes a distancecomponent 1610 that may determine a distance between the one or more UEsand each of the one or more mobile relays, e.g., as described inconnection with 806 of FIG. 8. The apparatus includes an assistanceinformation component 1612 that may send assistance information to atleast one of the one or more UEs in an area, e.g., as described inconnection with 808 of FIG. 8. The apparatus includes a determinationcomponent 1614 that may determine if the base station is capable ofsupporting an additional mobile relay, e.g., as described in connectionwith 1402 of FIG. 14. The apparatus includes a transmission component1616 that may be configured to transmit various types ofsignals/messages and/or other information to other devices, including,for example, the mobile relay 1650 or the UE 1660. The transmissioncomponent 1616 may transmit an indication whether the base station iscapable of accepting the additional mobile relay, e.g., as described inconnection with 1404 of FIG. 14.

The apparatus may include additional components that perform each of theblocks of the algorithm in the aforementioned flowcharts of FIGS. 8 and14. As such, each block in the aforementioned flowcharts of FIGS. 8 and14 may be performed by a component and the apparatus may include one ormore of those components. The components may be one or more hardwarecomponents specifically configured to carry out the statedprocesses/algorithm, implemented by a processor configured to performthe stated processes/algorithm, stored within a computer-readable mediumfor implementation by a processor, or some combination thereof.

FIG. 17 is a diagram 1700 illustrating an example of hardwareimplementation for an apparatus 1602′ employing a processing system1714. The processing system 1714 may be implemented with a busarchitecture, represented generally by the bus 1724. The bus 1724 mayinclude any number of interconnecting buses and bridges depending on thespecific application of the processing system 1714 and the overalldesign constraints. The bus 1724 links together various circuitsincluding one or more processors and/or hardware components, representedby the processor 1704, the components 1604, 1606, 1608, 1610, 1612,1614, 1616, and the computer-readable medium/memory 1706. The bus 1724may also link various other circuits such as timing sources,peripherals, voltage regulators, and power management circuits, whichare well known in the art, and therefore, will not be described anyfurther.

The processing system 1714 may be coupled to a transceiver 1710. Thetransceiver 1710 is coupled to one or more antennas 1720. Thetransceiver 1710 provides a means for communicating with various otherapparatus over a transmission medium. The transceiver 1710 receives asignal from the one or more antennas 1720, extracts information from thereceived signal, and provides the extracted information to theprocessing system 1714, specifically the reception component 1604. Inaddition, the transceiver 1710 receives information from the processingsystem 1714, specifically the transmission component 1616, and based onthe received information, generates a signal to be applied to the one ormore antennas 1720. The processing system 1714 includes a processor 1704coupled to a computer-readable medium/memory 1706. The processor 1704 isresponsible for general processing, including the execution of softwarestored on the computer-readable medium/memory 1706. The software, whenexecuted by the processor 1704, causes the processing system 1714 toperform the various functions described supra for any particularapparatus. The computer-readable medium/memory 1706 may also be used forstoring data that is manipulated by the processor 1704 when executingsoftware. The processing system 1714 further includes at least one ofthe components 1604, 1606, 1608, 1610, 1612, 1614, 1616. The componentsmay be software components running in the processor 1704,resident/stored in the computer readable medium/memory 1706, one or morehardware components coupled to the processor 1704, or some combinationthereof. The processing system 1714 may be a component of the basestation 310 and may include the memory 376 and/or at least one of the TXprocessor 316, the RX processor 370, and the controller/processor 375.Alternatively, the processing system 1714 may be the entire base station(e.g., see 310 of FIG. 3).

In one configuration, the apparatus 1602/1602′ for wirelesscommunication includes means for means for receiving first locationinformation for one or more UEs. The apparatus includes means forreceiving second location information for one or more mobile relays. Theapparatus includes means for determining a distance between the one ormore UEs and each of the one or more mobile relays. The apparatusincludes means for sending assistance information to at least one of theone or more UEs in an area. The assistance information identifying atleast one mobile relay of the one or more mobile relays based on thedetermined distance between the one or more UEs and the at least onemobile relay. The apparatus may further include means for receiving arequest from a UE, wherein the assistance information is sent to the UEin response to the request from the UE. The apparatus includes means fordetermining if the base station is capable of supporting an additionalmobile relay based on a current load of the base station. The apparatusincludes means for transmitting an indication indicating whether thebase station is capable of accepting the additional mobile relay. Theaforementioned means may be one or more of the aforementioned componentsof the apparatus 1602 and/or the processing system 1714 of the apparatus1602′ configured to perform the functions recited by the aforementionedmeans. As described supra, the processing system 1714 may include the TXProcessor 316, the RX Processor 370, and the controller/processor 375.As such, in one configuration, the aforementioned means may be the TXProcessor 316, the RX Processor 370, and the controller/processor 375configured to perform the functions recited by the aforementioned means.

FIG. 18 is a conceptual data flow diagram 1800 illustrating the dataflow between different means/components in an example apparatus 1802.The apparatus may be a UE or a component of a UE. The apparatus includesa reception component 1804 that may be configured to receive varioustypes of signals/messages and/or other information from other devices,including, for example, the base station 1850 or the mobile relay 1860.The apparatus includes a location component 1806 that may providelocation information to a base station, e.g., as described in connectionwith 902 of FIG. 9. The apparatus includes an assistance informationcomponent 1808 that may receive, from a network entity, assistanceinformation that may identify at least one mobile relay within adistance of the UE, e.g., as described in connection with 904 of FIG. 9.The apparatus includes a discovery component 1810 that may performdiscovery for a mobile relay, e.g., as described in connection with 906of FIG. 9. The apparatus includes a selection component 1812 that mayselect a mobile relay for relaying communication from the UE to a basestation, e.g., as described in connection with 908 of FIG. 9. Theapparatus includes a communication component 1814 that may communicatewith the base station without the mobile relay when the UE is unable todiscover the mobile relay, e.g., as described in connection with 910 ofFIG. 9. The apparatus includes a request component 1816 that may send arequest to the network entity, e.g., as described in connection with 912of FIG. 9. The apparatus includes an identifier component 1818 that mayreceive an identifier from a mobile relay, e.g., as described inconnection with 1102 of FIG. 11. The apparatus includes a PCI component1820 that may determine the PCI of the mobile relay from the receivedidentifier, e.g., as described in connection with 1104 of FIG. 11. Theapparatus includes a report component 1822 that may report the PCI ofthe mobile relay to a network entity, e.g., as described in connectionwith 1106 of FIG. 11. The apparatus includes an indication component1824 that may receive an indication from a mobile relay indicatingwhether the mobile relay is accepting an additional UE, e.g., asdescribed in connection with 1302 of FIG. 13. The apparatus includes arelay component 1826 that may select a relay for communication with anetwork, e.g., as described in connection with 1306 of FIG. 13. Theapparatus includes a priority component 1828 that may assign the mobilerelay a reduced priority in a candidate list when the indicationindicates that the mobile relay is not accepting the additional UE,e.g., as described in connection with 1304 of FIG. 13.

The apparatus may include additional components that perform each of theblocks of the algorithm in the aforementioned flowcharts of FIGS. 9, 11,and 13. As such, each block in the aforementioned flowcharts of FIGS. 9,11, and 13 may be performed by a component and the apparatus may includeone or more of those components. The components may be one or morehardware components specifically configured to carry out the statedprocesses/algorithm, implemented by a processor configured to performthe stated processes/algorithm, stored within a computer-readable mediumfor implementation by a processor, or some combination thereof.

FIG. 19 is a diagram 1900 illustrating an example of a hardwareimplementation for an apparatus 1802′ employing a processing system1914. The processing system 1914 may be implemented with a busarchitecture, represented generally by the bus 1924. The bus 1924 mayinclude any number of interconnecting buses and bridges depending on thespecific application of the processing system 1914 and the overalldesign constraints. The bus 1924 links together various circuitsincluding one or more processors and/or hardware components, representedby the processor 1904, the components 1804, 1806, 1808, 1810, 1812,1814, 1816, 1818, 1820, 1822, 1824, 1826, 1828, 1830, and thecomputer-readable medium / memory 1906. The bus 1924 may also linkvarious other circuits such as timing sources, peripherals, voltageregulators, and power management circuits, which are well known in theart, and therefore, will not be described any further.

The processing system 1914 may be coupled to a transceiver 1910. Thetransceiver 1910 is coupled to one or more antennas 1920. Thetransceiver 1910 provides a means for communicating with various otherapparatus over a transmission medium. The transceiver 1910 receives asignal from the one or more antennas 1920, extracts information from thereceived signal, and provides the extracted information to theprocessing system 1914, specifically the reception component 1804. Inaddition, the transceiver 1910 receives information from the processingsystem 1914, specifically the transmission component 1830, and based onthe received information, generates a signal to be applied to the one ormore antennas 1920. The processing system 1914 includes a processor 1904coupled to a computer-readable medium/memory 1906. The processor 1904 isresponsible for general processing, including the execution of softwarestored on the computer-readable medium/memory 1906. The software, whenexecuted by the processor 1904, causes the processing system 1914 toperform the various functions described supra for any particularapparatus. The computer-readable medium/memory 1906 may also be used forstoring data that is manipulated by the processor 1904 when executingsoftware. The processing system 1914 further includes at least one ofthe components 1804, 1806, 1808, 1810, 1812, 1814, 1816, 1818, 1820,1822, 1824, 1826, 1828, 1830. The components may be software componentsrunning in the processor 1904, resident/stored in the computer readablemedium/memory 1906, one or more hardware components coupled to theprocessor 1904, or some combination thereof. The processing system 1914may be a component of the UE 350 and may include the memory 360 and/orat least one of the TX processor 368, the RX processor 356, and thecontroller/processor 359. Alternatively, the processing system 1914 maybe the entire UE (e.g., see 350 of FIG. 3).

In one configuration, the apparatus 1802/1802′ for wirelesscommunication includes means for providing location information for theUE to a base station. The apparatus includes means for receiving, from anetwork entity, assistance information identifying at least one mobilerelay within a distance of the UE. The apparatus further includes meansfor performing discovery for a mobile relay based on the assistanceinformation provided from the network entity. The apparatus furtherincludes means for selecting a mobile relay for relaying communicationfrom the UE to a base station based on the assistance informationreceived from the network entity. The apparatus further includes meansfor communicating with the base station without the mobile relay whenthe UE cannot discover a mobile relay, including the at least one mobilerelay identified in the assistance information. The apparatus furtherincludes means for sending a request to the network entity, wherein theUE receives the assistance information in response to the request. Theapparatus includes means for receiving an identifier from a mobile relayindicating a PCI for the mobile relay. The apparatus includes means fordetermining the PCI of the mobile relay from the received identifier.The apparatus includes means for receiving an indication from a mobilerelay indicating whether the mobile relay is accepting an additional UE.The apparatus includes means for selecting a relay for communicationwith a network based in part on the indication from the mobile relay.The apparatus further includes means for giving the mobile relay areduced priority in a candidate list or removing the mobile relay fromthe candidate list when the indication indicates that the mobile relayis not accepting the additional UE. The aforementioned means may be oneor more of the aforementioned components of the apparatus 1802 and/orthe processing system 1914 of the apparatus 1802′ configured to performthe functions recited by the aforementioned means. As described supra,the processing system 1914 may include the TX Processor 368, the RXProcessor 356, and the controller/processor 359. As such, in oneconfiguration, the aforementioned means may be the TX Processor 368, theRX Processor 356, and the controller/processor 359 configured to performthe functions recited by the aforementioned means.

FIG. 20 is a conceptual data flow diagram 2000 illustrating the dataflow between different means/components in an example apparatus 2002.The apparatus may be a mobile relay or a component of a mobile relay.The apparatus includes a reception component 2004 that may be configuredto receive various types of signals/messages and/or other informationfrom other devices, including, for example, the base station 2050 or theUE 2060. The apparatus includes an identifier component 2006 that maygenerate an identifier, e.g., as described in connection with 1002 ofFIG. 10. The apparatus includes a determination component 2008 that maydetermine if the mobile relay device is capable of supporting anadditional UE, e.g., as described in connection with 1202 of FIG. 12.The apparatus includes an indication component 2010 that may receive anindication from a base station indicating whether the base station isaccepting an additional mobile relay, e.g., as described in connectionwith 1502 of FIG. 15. The apparatus includes a camp component 2012 thatmay determine whether to camp on the base station, e.g., as described inconnection with 1506 of FIG. 15. The apparatus includes a prioritycomponent 2014 that may give the base station a reduced priority in acandidate list when the indication indicates that the base station isnot accepting the additional mobile relay, e.g., as described inconnection with 1504 of FIG. 15. The apparatus includes a transmissioncomponent 2016 that may broadcast the identifier, e.g., as described inconnection with 1004 of FIG. 10. The transmission component 2016 maytransmit an indication indicating whether the mobile relay device iscapable of accepting the additional UE, e.g., as described in connectionwith 1204 of FIG. 12.

The apparatus may include additional components that perform each of theblocks of the algorithm in the aforementioned flowcharts of FIGS. 10,12, and 15. As such, each block in the aforementioned flowcharts ofFIGS. 10, 12, and 15 may be performed by a component and the apparatusmay include one or more of those components. The components may be oneor more hardware components specifically configured to carry out thestated processes/algorithm, implemented by a processor configured toperform the stated processes/algorithm, stored within acomputer-readable medium for implementation by a processor, or somecombination thereof.

FIG. 21 is a diagram 2100 illustrating an example of a hardwareimplementation for an apparatus 2002′ employing a processing system2114. The processing system 2114 may be implemented with a busarchitecture, represented generally by the bus 2124. The bus 2124 mayinclude any number of interconnecting buses and bridges depending on thespecific application of the processing system 2114 and the overalldesign constraints. The bus 2124 links together various circuitsincluding one or more processors and/or hardware components, representedby the processor 2104, the components 2004, 2006, 2008, 2010, 2012,2014, 2016, and the computer-readable medium/memory 2106. The bus 2124may also link various other circuits such as timing sources,peripherals, voltage regulators, and power management circuits, whichare well known in the art, and therefore, will not be described anyfurther.

The processing system 2114 may be coupled to a transceiver 2110. Thetransceiver 2110 is coupled to one or more antennas 2120. Thetransceiver 2110 provides a means for communicating with various otherapparatus over a transmission medium. The transceiver 2110 receives asignal from the one or more antennas 2120, extracts information from thereceived signal, and provides the extracted information to theprocessing system 2114, specifically the reception component 2004. Inaddition, the transceiver 2110 receives information from the processingsystem 2114, specifically the transmission component 2016, and based onthe received information, generates a signal to be applied to the one ormore antennas 2120. The processing system 2114 includes a processor 2104coupled to a computer-readable medium/memory 2106. The processor 2104 isresponsible for general processing, including the execution of softwarestored on the computer-readable medium/memory 2106. The software, whenexecuted by the processor 2104, causes the processing system 2114 toperform the various functions described supra for any particularapparatus. The computer-readable medium/memory 2106 may also be used forstoring data that is manipulated by the processor 2104 when executingsoftware. The processing system 2114 further includes at least one ofthe components 2004, 2006, 2008, 2010, 2012, 2014, 2016. The componentsmay be software components running in the processor 2104,resident/stored in the computer readable medium/memory 2106, one or morehardware components coupled to the processor 2104, or some combinationthereof. The processing system 2114 may be a component of the mobilerelay. Alternatively, the processing system 2114 may be the entiremobile relay.

In one configuration, the apparatus 2002/2002′ for wirelesscommunication includes means for generating an identifier that enables aUE to derive a PCI for the mobile relay device. The apparatus includesmeans for broadcasting the identifier. The apparatus includes means fordetermining if the mobile relay device is capable of supporting anadditional UE based on a current load of the mobile relay device. Theapparatus includes means for transmitting an indication indicatingwhether the mobile relay device is capable of accepting the additionalUE. The apparatus includes means for receiving an indication from a basestation indicating whether the base station is accepting an additionalmobile relay. The apparatus includes means for determining whether tocamp on the base station based on the indication from the base stationas a donor base station. The apparatus further includes means for givingthe base station a reduced priority in a candidate list or removing thebase station from the candidate list when the indication indicates thatthe base station is not accepting the additional mobile relay. Theaforementioned means may be one or more of the aforementioned componentsof the apparatus 2002 and/or the processing system 2114 of the apparatus2002′ configured to perform the functions recited by the aforementionedmeans.

The present disclosure relates to discovery procedures of relays inwireless communication systems. Base stations may have a limitedcoverage area, and including relay nodes in the wireless communicationsystem may allow the relay node to provide additional coverage that maynot be provided by the limited coverage area of a base station. Mobilerelays are relays placed in a vehicle and may provide coverage toneighboring UEs, which can be in the vehicle itself or in the vicinityof the vehicle. Base stations maintain neighbor lists which contain alist of neighboring cells, and the list of neighboring cells that a UEis expected to see and potentially handover to is known and fixed. Inwireless communication systems that include relays, e.g., mobile relays,the relays providing service to UEs may be mobile, such that a list ofneighboring relays that the UE is expected to see on a particular relaymay repeatedly change. Aspects provided herein provide a solution to theproblem of dynamically updating the neighbor list sent to the UE, basedon the location of the UE and/or the location of the relay. In someaspects, a network entity may send assistance information to at leastone UE, in an area, where the assistance information identifies at leastone mobile relay in the vicinity of the at least one UE, such that theat least one UE may discover and determine whether or not to select theat least one mobile relay for relaying communication from the UE to thenetwork. At least one advantage of the disclosure is that the networkentity may determine the neighboring mobile relays based on the distancebetween the UE and the neighboring mobile relays. At least anotheradvantage of the disclosure is that a UE may be configured to discoveravailable mobile relays in a more efficient manner, while minimizing theamount of reselections to a new mobile relay.

It is understood that the specific order or hierarchy of blocks in theprocesses/flowcharts disclosed is an illustration of example approaches.Based upon design preferences, it is understood that the specific orderor hierarchy of blocks in the processes/flowcharts may be rearranged.Further, some blocks may be combined or omitted. The accompanying methodclaims present elements of the various blocks in a sample order, and arenot meant to be limited to the specific order or hierarchy presented.

The previous description is provided to enable any person skilled in theart to practice the various aspects described herein. Variousmodifications to these aspects will be readily apparent to those skilledin the art, and the generic principles defined herein may be applied toother aspects. Thus, the claims are not intended to be limited to theaspects shown herein, but is to be accorded the full scope consistentwith the language claims, wherein reference to an element in thesingular is not intended to mean “one and only one” unless specificallyso stated, but rather “one or more.” The word “exemplary” is used hereinto mean “serving as an example, instance, or illustration.” Any aspectdescribed herein as “exemplary” is not necessarily to be construed aspreferred or advantageous over other aspects. Unless specifically statedotherwise, the term “some” refers to one or more. Combinations such as“at least one of A, B, or C,” “one or more of A, B, or C,” “at least oneof A, B, and C,” “one or more of A, B, and C,” and “A, B, C, or anycombination thereof” include any combination of A, B, and/or C, and mayinclude multiples of A, multiples of B, or multiples of C. Specifically,combinations such as “at least one of A, B, or C,” “one or more of A, B,or C,” “at least one of A, B, and C,” “one or more of A, B, and C,” and“A, B, C, or any combination thereof” may be A only, B only, C only, Aand B, A and C, B and C, or A and B and C, where any such combinationsmay contain one or more member or members of A, B, or C. All structuraland functional equivalents to the elements of the various aspectsdescribed throughout this disclosure that are known or later come to beknown to those of ordinary skill in the art are expressly incorporatedherein by reference and are intended to be encompassed by the claims.Moreover, nothing disclosed herein is intended to be dedicated to thepublic regardless of whether such disclosure is explicitly recited inthe claims. The words “module,” “mechanism,” “element,” “device,” andthe like may not be a substitute for the word “means.” As such, no claimelement is to be construed as a means plus function unless the elementis expressly recited using the phrase “means for.”

What is claimed is:
 1. A method of wireless communication for a networkentity, comprising: receiving first location information for one or moreuser equipments (UEs); receiving second location information for one ormore mobile relays; determining a distance between the one or more UEsand each of the one or more mobile relays; and sending assistanceinformation to at least one of the one or more UEs in an area, theassistance information identifying at least one mobile relay of the oneor more mobile relays based on the determined distance between the oneor more UEs and the at least one mobile relay.
 2. The method of claim 1,wherein the network entity receives the first location information forthe one or more UEs and the second location information for the one ormore mobile relays from another network entity or directly from the oneor more UEs.
 3. The method of claim 1, wherein the network entity sendsthe assistance information to the at least one of the one or more UEs indedicated signaling comprising a radio resource control (RRC) messagefor the at least one of the one or more UEs.
 4. The method of claim 1,wherein the network entity broadcasts the assistance information insystem information.
 5. The method of claim 1, wherein communication forthe one or more UEs is transmitted using a first frequency band, andwherein the assistance information is transmitted to the at least one ofthe one or more UEs using a second frequency band that is different thanthe first frequency band.
 6. The method of claim 1, further comprising:receiving a request from a UE, wherein the assistance information issent to the UE in response to the request from the UE, and wherein theassistance information includes a temporarily restricted list of mobilerelays.
 7. A method of wireless communication at a user equipment (UE),comprising: providing location information for the UE to a base station;and receiving, from a network entity, assistance information identifyingat least one mobile relay within a distance of the UE.
 8. The method ofclaim 7, further comprising: performing discovery for a mobile relay forrelaying communication from the UE to a base station based on theassistance information provided from the network entity; and. selectingthe mobile relay based on the performed discovery.
 9. The method ofclaim 8, further comprising: communicating with the base station withoutthe mobile relay when the UE cannot discover a mobile relay, includingthe at least one mobile relay identified in the assistance information.10. The method of claim 7, wherein UE provides the location informationfor the UE to the network entity or to another network entity.
 11. Themethod of claim 7, wherein the UE receives the assistance informationfrom the network entity in dedicated signaling comprising a radioresource control (RRC) message for the UE.
 12. The method of claim 7,wherein the UE receives the assistance information in broadcast systeminformation.
 13. The method of claim 7, wherein the UE receives datausing a first frequency band, and wherein the UE receives the assistanceinformation using a second frequency band that is different than thefirst frequency band.
 14. The method of claim 7, further comprising:sending a request to the network entity, wherein the UE receives theassistance information in response to the request, and the assistanceinformation includes a restricted list of mobile relays.
 15. The methodof claim 7, further comprising: receiving an identifier from anothermobile relay indicating a physical cell identity (PCI) for the anothermobile relay; and determining the PCI of the another mobile relay fromthe received identifier.
 16. The method of claim 15, wherein the UEreceives the identifier in a broadcast based on a PC5 communication fromthe another mobile relay.
 17. The method of claim 15, furthercomprising: reporting the PCI of the another mobile relay to anothernetwork entity.
 18. The method of claim 7, comprising: receiving anindication from another mobile relay indicating whether the anothermobile relay is accepting an additional UE; and selecting a relay forcommunication with a network based in part on the indication from theanother mobile relay.
 19. The method of claim 18, further comprising:giving the another mobile relay a reduced priority in a candidate listor removing the mobile relay from the candidate list when the indicationindicates that the mobile relay is not accepting the additional UE. 20.The method of claim 18, wherein the UE receives the indication in abroadcast from the another mobile relay, as system information based ona Uu interface, or as system information based on device-to-devicecommunication.
 21. A method of wireless communication at a mobile relaydevice, comprising: determining if the mobile relay device is capable ofsupporting an additional user equipment (UE) based on a current load ofthe mobile relay device; and transmitting an indication indicatingwhether the mobile relay device is capable of accepting the additionalUE.
 22. The method of claim 21, wherein the mobile relay devicebroadcasts the indication as system information using a Uu interface ordevice-to-device communication.
 23. The method of claim 21, furthercomprising: generating an identifier that enables a user equipment (UE)to derive a physical cell identity (PCI) for the mobile relay device;and broadcasting the identifier.
 24. The method of claim 23, wherein themobile relay device broadcasts the identifier using device-to-devicecommunication.
 25. The method of claim 21, further comprising: receivingan indication from a base station indicating whether the base station isaccepting an additional mobile relay device; and determining whether tocamp on the base station based on the indication from the base stationas a donor base station.
 26. The method of claim 25, further comprising:giving the base station a reduced priority in a candidate list orremoving the base station from the candidate list when the indicationindicates that the base station is not accepting the additional mobilerelay.
 27. The method of claim 25, wherein the mobile relay devicereceives the indication as system information broadcast from the basestation.
 28. A method of wireless communication at a base station,comprising: determining if the base station is capable of supporting anadditional mobile relay based on a current load of the base station; andtransmitting an indication indicating whether the base station iscapable of accepting the additional mobile relay.
 29. The method ofclaim 28, wherein the base station broadcasts the indication.
 30. Themethod of claim 28, wherein the base station broadcasts the indicationin system information.